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首页> 外文期刊>Journal of soil & sediments >High soil temperatures alter the rates of nitrification, denitrification and associated N_2O emissions
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High soil temperatures alter the rates of nitrification, denitrification and associated N_2O emissions

机译：较高的土壤温度会改变硝化，反硝化及相关N_2O排放的速率

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Purpose: The responses of nitrification and denitrification are not well characterised at temperatures above 35 degrees C, which is the focus of our study.Materials and methods Soils collected from two dairy pastures (Victoria, Australia) were incubated at 10 to 45 degrees C in the dark for 5 to 10 days following amendment with 100 mu g N g(-1) either as NH4NO3, (NH4NO3)-N-14-N-15 or (NH4NO3)-N-15-N-15 (10 atom% N-15 excess) at 50% water-filled pore space. To detect N2O from heterotrophic nitrification, acetylene (0.01% v/v) was used in a subset of samples amended with (NH4NO3)-N-15-N-15. Atom% N-15 enrichments of NO3-, N2O and N-2 were measured during the experiment to evaluate the responses of nitrification and denitrification to temperature.Results and discussion N2O production from the two soils increased with rising temperature and peaked between 35 and 40 degrees C. N2O production from nitrification and denitrification both had similar thermal responses, which were different to N-2 production. The N2O/N-2 ratio decreased from 4 at 35-40 degrees C to 0.5 at 45 degrees C, due to greater N-2 than N2O production in the Dermosol. Heterotrophic nitrifiers oxidised NH4+ and released N2O at 35-40 degrees C, suggesting a role for heterotrophs in N cycling under warm climates. T-opt for nitrification was between 35 and 40 degrees C, which is higher than reported previously. A short-term effect of high temperatures could provide NH4+ for the growth of crops but may also decrease soil C pools.Conclusions Increasing temperature above 35 degrees C altered the rates of nitrification, denitrification associated N2O and N-2 production. Nitrification and denitrification peaked at 35-40 degrees C in the Chromosol and Dermosol. The production of N-2 increased rapidly above 40 degrees C, which may be related to high soil respiration rates that likely decreased O-2 availability, thus expanding the anaerobic microsites; such circumstances increased the reduction of N2O to N-2 production from the Dermosol.
机译：目的：在高于35摄氏度的温度下无法很好地表征硝化和反硝化的响应，这是我们的研究重点。材料和方法从两个牧场（维多利亚州，澳大利亚）收集的土壤在10至45摄氏度下孵育。用100μg N g（-1）修正为NH4NO3，（NH4NO3）-N-14-N-15或（NH4NO3）-N-15-N-15（10原子％ N-15过量）在50％充满水的孔隙空间中。为了检测异养硝化反应中的N2O，在用（NH4NO3）-N-15-N-15修正的样品子集中使用乙炔（0.01％v / v）。在实验过程中，测定了原子含量的N-15，NO3-，N2O和N-2的N-15富集度，以评估硝化作用和反硝化作用对温度的响应。结果与讨论两种土壤中N2O的产生均随温度的升高而增加，并在35至40之间达到峰值。硝化和反硝化产生的N2O产生的热响应都相似，与N-2产生的不同。 N2O / N-2比例从35-40摄氏度时的> 4降至45摄氏度时的0.5，这是由于Dermosol中的N-2比N2O产生的要多。异养硝化剂在35-40摄氏度下氧化NH4 +并释放N2O，这表明异养生物在温暖气候下在氮循环中的作用。硝化作用的T-opt温度介于35到40摄氏度之间，高于先前报道的水平。高温的短期影响可以为作物的生长提供NH4 +，但也可能减少土壤碳库。结论温度升高到35摄氏度以上会改变硝化，反硝化相关的N2O和N-2产生的速率。在铬溶胶和真皮溶胶中，硝化作用和反硝化作用在35-40℃时达到峰值。在40摄氏度以上时，N-2的产量迅速增加，这可能与土壤呼吸速率高有关，这可能降低了O-2的利用率，从而扩大了厌氧微生物的产地。这种情况增加了Dermosol将N2O还原为N-2的产量。

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